When a plate-like workpiece is to be cut into a rectangular shape for example, laser cutting may be performed. A workpiece that has been cut into a rectangular shape as described above by laser cutting may be subjected to bending along a long bending line in a longitudinal direction of the workpiece. When laser cutting is performed on the plate-like workpiece, residual stress occurs near a cut edge of the workpiece. As exemplified in Japanese Patent Application Laid-open No. 2012-157902 (Patent Literature 1), when the shape of the workpiece cut into a rectangular shape as described above has a strip shape, it has been known that residual stress at the cut edge in the longitudinal direction of the workpiece affects warpage of the workpiece after bending. Further, as exemplified in Japanese Patent Application Laid-open No. 2013-116502 (Patent Literature 2), a mold for reducing residual stress has been proposed.